Articles by Dr. Francis Gouin

The combination of saturated soil and strong winds has tilted trees and tall shrubs. If the trunk of a tilted tree is thicker than four ­inches, it is unlikely that the tree can be straightened and remain upright without permanent support. This is also true of large shrubs. The problem lies with the inability of roots larger than two inches in diameter to regenerate and develop sufficient size to stabilize the plant.
This spring I have seen several large arborvitae, spruce and maple trees that appeared to have been blown over now supported with ropes and cables in an effort to straighten them. In most instances this is futile without a permanent brace, especially if the plant is part of a hedge or screen. In this case the problem is not only the plant’s inability to generate new roots from the large roots but also root competition from surrounding plants.
Another problem associated with trying to straighten a large tree or shrub is girdling. Wrapping a cable, chain or rope around the stem of a plant and leaving it for more than a year will strangulate it. As the diameter of the stem increases, the binding will prevent the stem from enlarging above the point of contact, resulting in death of the higher portions. Whenever wrapping anything around a growing stem, readjust the ties periodically and pad them with wide straps or slats of vinyl or wood to distribute the pressure on the stem.
Where plants growing in a screen or hedge have been blown over, it is generally best to remove the plant and allow the adjoining plants to fill in the space. With competition removed, nearby branches will occupy the vacant space with surprising speed. A common practice in commercial nurseries is to dig every other plant, allowing the remaining ones to nearly double their size in half the normal time because of less competition for light, water and nutrients.
The problems with replacing blown-over plants with new plants is matching the existing plants in size, shape and color. After new plants are in place, they must be kept properly irrigated because the roots of surrounding established plants have a greater capacity to absorb water.
Narrow-leaf evergreen screens and hedges have another problem, especially if they are dense, in bottom branches with no live needles. Unlike deciduous trees and shrubs, narrow-leaf evergreens are not able to grow new branches after needles have fallen. The complete loss of live green needles means death to that branch. Thus, for trees like arborvitae, pine, spruce, juniper, fir and chamaecyparis, dead-looking brown, brittle branches will never turn green again.

Free Gita Bean Seeds

Over the years, I have recommended growing Gita pole beans in your garden. Fully mature, Gita beans will grow to a length of almost three feet. However, harvested when they are about 12" to 18" long with a diameter of a pencil, they are tasty and tender. Gita perform best in the heat of summer in full sun. The plants will grow up to 10 feet in height and will flower and produce fruit simultaneously. For the past two years I have been collecting seeds and testing them.
If you would like to try growing Gita beans, send me a self-addressed stamped envelope, and I will return to you a dozen or more seeds. Send your letter to F.R. Gouin, 420 E. Bay Front Rd., Deale, MD 20751.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

This has been a great year for asparagus. Spears are popping out of the ground daily, growing four to six inches in one day. I find it best to cut the asparagus just below the soil line and harvest spears that are at least six inches above ground. This allows you to snap the bottom of the stem, which guarantees they will be free of woody tissues. Keep asparagus beds free of weeds by hoeing weekly. To avoid promoting additional weed growth, scrape away the weeds with minimal disturbance of the soil.
If your asparagus bed has been growing for three years or more, it is safe to harvest spears until early July.
Within days after the last harvest, top dress the bed with either organic or chemical fertilizer, and cultivate the fertilizer into the soil to minimize the loss of nitrogen into the atmosphere. Soil incorporation of fertilizers is the only effective way of minimizing de-nitrification. To minimize weeding, mulch the asparagus bed with a layer of shredded paper about four inches thick.
Soon broccoli, cabbage, cauliflower, Chinese cabbage and kohlrabi will be ready to harvest. A good replacement crop to occupy this vacant space is okra. For a jumpstart on okra, sow individual seeds in two- or three-inch pots filled with potting soil. Place one seed per pot because okra seeds germinate 100 percent within 10 days. As soon as the seeds germinate, place the pots in full sun outdoors and water as needed. In three to four weeks, the plants will be ready to transplant 18 inches apart in the garden. Okra plants grow best when the weather gets hot. Plants started in a protected area will quickly establish themselves in the garden.
If you planted garlic in the fall, be on the lookout for firm round stems growing from the middle of the whorl of leaves. These round stems are an indication that the plants are going to flower. As soon as you see swelling near the end of the round stem, cut just below the swollen area to remove the premature flower head. Allowing garlic to flower and produce seeds will result in smaller garlic bulbs and cloves.
As soon as the foliage of garlic plants starts to wilt and turns brownish-green, it is ready to harvest. Soft-neck garlic can be braided at this time. Hard-neck garlic cannot be braided and is best stored by tying in loose bunches before hanging in a shaded and well-ventilated area.
If you use stakes or cages to support your tomato plants, treat the cages and stakes with a solution of one part bleach to nine parts water.
Watch the bottom leaves on your tomato plants. When they start to turn yellow-green, it is time to side-dress the plants with additional nitrogen. If you are an organic gardener, your best source of nitrogen is blood meal. If you are a traditional gardener, use calcium nitrate. Either way, apply one-fourth cup fertilizer per plant and cultivate into the soil.
As soon as cucumbers, melons and squash start to produce vines, they should be given additional nitrogen if they are to yield their best crop. Vine crops also benefit from additional nitrogen when they are extending their vines and producing fruit at the same time.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Am I an organic gardener? I’m often asked that question. I suspect that many who read this column conclude that my frequent reference to composting and compost in gardening means I must be an organic gardener. They seem shocked when I say that I use chemical fertilizers in addition to amending my soils with compost. My reasoning is that of a scientist.
Before my research into compost, my primary area of research was mineral nutrition of plants. My research for the thesis for my master’s degree resulted in the development of a slow-release fertilizer marketed as Osmocote 18-6-12. The three-year study was conducted on yews, a narrow-leaf evergreen common in landscape plantings. At the time, the nursery industry was starting to grow more plants in pots. Nurserymen were using the same fertilizers as in field production. The two are totally different growing conditions. Plants growing in pots require more frequent irrigation, which washes more nutrients through the bottom of the pots. Plants grow faster in pots because of high rooting-media temperatures and better aeration. But the rooting media used for growing plants in pots do not store nutrients well.
My research and reviews of the results of many other plant-nutrient experts convinced me that it can be very difficult to satisfy the nutrient requirements of plants at different stages of growth.
My later work in the use of compost in the production of nursery and greenhouse crops reinforced the conclusion that it takes both organic and mineral fertilizers to achieve both plant health and high crop yields.
In the spring when soils are cool, compost, animal manure and organic fertilizers are unable to generate sufficient nutrients because they require microbial activity to release nutrients. For spring-planted crops such as peas, cabbage, broccoli, onions and cauliflower, chemical fertilizers can provide those nutrients.
Again when tomato and pepper plants are flowering and fruiting simultaneously, the demand for nitrogen is greater than organics are capable of generating. Plants drop bottom leaves because the nitrogen within them is migrating out of the leaves and moving up the stem. This makes the plants more susceptible to blight.
In mid-summer when sweet corn is growing rapidly in advance of tasseling, organics are not capable of generating sufficient nitrogen for big, sweet ears. Thus the corn stalks drop their bottom leaves.
We know from studies on the use of compost to grow bedding plants that the nutrient-supplying power of rooting media containing compost can supply adequate levels of nutrients for only about six weeks.
Nitrogen is the element plants need in greatest abundance. Organic matter is incapable of supplying all that is needed. Numerous research studies have confirmed my initial research that most plants require five to six times more nitrogen that phosphorus and two to three times more potassium than phosphorus. As day length, moisture and temperature affect plant growth, using the combination of soils rich in organic matter with supplemental applications of chemical fertilizers gives you the best of both worlds.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Horticulture is a science, not a guessing game.
I can remember my pipe-smoking, tobacco-chewing grandfather putting garden soil in his mouth to taste if it was sweet or sour. I was impressed at the time, but looking back on his method of testing soil, I know it would have been impossible for him to make any determinations of the pH or of nutrients by taste.
Just as doctors rely on blood tests as guides to their patients’ health, in agriculture, we rely on soil test results. Soil testing supports both the health and nutrient value of plants. A deficiency of one or two essential soil nutrients reduces not only yields but also the level of nutrients within plant tissues that will be ingested by humans or animals. Soil that is deficient in zinc, copper, iron, magnesium, calcium, etc. will produce plants that are equally deficient, which will have a direct effect on your health.
If you have applied 10-10-10 fertilizer on your garden or lawn for many years, it is likely that your soil has too much phosphorus. That excess can, in turn, result in reduced crop yields and plants deficient in zinc, iron, copper and manganese. The excess phosphorus binds these nutrients, making them unavailable to the roots of plants.
This is the problem farmers experience from repeated applications of chicken manure, which is rich in phosphorus. In that case, the excess phosphorus in the soil is making the soybeans or corn grown there deficient in essential elements. Humans or animals eating those grains will not get a nutritionally balanced diet.
Too much phosphorus causes still more problems. When soil erodes and enters Bay waters, phosphorus attaches to clay particles. When these clay-laden soils penetrate silt fences and enter the Bay, the phosphorus is released, adding to the water’s nutrient-concentration problems.
Another element, boron, is also secretly at work in your soil. If you are gardening in a sandy loam or loamy sand, boron deficiency is likely. Plants do not require much boron, but its deficiency affects yields and storage life. You have likely seen the result without recognizing it. The brown punky blotches you sometimes see beneath the skin of an apple tell you that the fruit was grown on boron-deficient soil.
Without soil testing, you won’t know the invisible forces at work in your soil.
I can now give you a choice of two laboratories for your soil testing:
• A&L Eastern Agricultural Laboratory, now known as Waypoint: www.al-labs-eastern.com (804-743-9401; 7621 Whitepine Dr., Richmond, VA 23237).
• AgroLab, Inc.: www.agrolab.us (302-566-6094; 101 Clukey Dr., Harrington, DE 19952). Request a soil-testing kit, including instructions on how to take qualitative soil samples.
Include my e-mail address (dr.frgouin@gmail.com) on the information sheet to have results sent to me for interpretation. Include your own e-mail address as well so I can forward you my recommendations.
Good recommendations depend on a good sample. To represent your current soil conditions, take at least five core samples to a depth of six inches in six different locations in your lawn or garden. Mix the core samples thoroughly in a clean container. Remove about a cup of soil for testing. Spread the sample on a clean piece of newsprint to dry overnight before mailing. On the form, identify what’s to grow in that area. Results are typically returned within a week.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

There is nothing like sneaking into the garden in mid to late July after the potato plants have finished flowering and stealing a few thin-skinned potatoes. If you hill your potatoes with compost in place of garden soil, you can harvest potatoes without disturbing the plant. At the final harvest, you get the added benefit of potatoes that are almost dirt-free.
Freshly dug potatoes have a flavor all their own. Mashed, they are nice and fluffy; French-fried, they are always golden and absorb very little cooking oil; baked, they are outstandingly delicious. They bring all these advantages because they are nearly 100 percent starch. As their thin skin needs no peeling, they are packed with vitamins that concentrated immediately under the skin. If you like hash brown potatoes with onions, your garden can provide both because the long-day onions you plant this spring will be bulbing at about the same time you start taking potatoes from the plants.
Hilling potatoes with immature yard-debris compost in place of garden soil has many advantages. First, it forces you to generate an abundance of compost because it takes a lot to hill potatoes. By the time the potato plants are two feet tall, you will have had to hill them at least three times. For a row 80 feet long, that’s at least five wheelbarrows full. Purchasing that much compost would cost you a pretty penny. Furthermore, the compost you purchase is finished and heavy to handle. Immature compost from the composting bin that you filled last fall has a large amount of partially decomposed leaves mixed with more fully decomposed materials, making it less dense and easy to transport and apply.
Second, by hilling the potato plants with compost, you can easily push your hands in until you feel an edible potato. As long as you gently remove the potato from the rhizome, you do not retard the growth of the plant.
Third, as immature compost does not absorb much water, even the smallest rain will penetrate down into the soil where most of the roots that feed the plants are located.
Fourth, potato beetles do not appear to be as problematic on potatoes hilled with unfinished compost. Entomologists tell me that adult potato beetles are not good navigators. They have no problem taking off, but when it comes to landing, they often miss their target. Instead of flying back to the plant they missed, they walk on the soil. They appear not to like walking on rough surfaces such as unfinished compost. Thus, when hilling with unfinished compost, keep the leaves of the plants from touching the ground.
There are many years I have not had to spray for beetles. A daily walk through the planting to remove the beetles by hand, dropping them into a container, is all that has been necessary.
Fifth, by hilling with compost you have added to the organic matter of your garden soil. By rotating my potato planting every year, I manage to apply a uniform layer of compost over the entire garden every five years.
All that and delicious young potatoes, too.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Those white webs expanding in the crotches of cherry, crabapple and Juneberry trees are made by eastern tent caterpillars. Last summer and early fall, the adults laid their eggs in these favorite trees. As the larvae emerge, they spin a web around the nest, giving it protection from the weather. In the evening, the larvae crawl out from under the web to feed on nearby tender young leaves. Just about the time the sun rises, they return to the web for protection. As the population of larvae increases and the larvae increase in size, so does the webbing of the nest.
As long as the larvae remain under the protection of the web, they are protected from birds and the elements as well as from insecticidal sprays. You will never see birds feasting on these webs. If you poke your finger into one, you will see why birds do not bother them.
“The defoliation usually does little damage to trees, and rarely do trees die from an infestation,” says Maryland Agriculture Secretary Joe Bartenfelder.
The lack of damage is due to timing. Because the caterpillars hatch as soon as the young leaves unfurl in the spring, the tree has put little energy into the leaves and typically re-foliates in June, seemingly no worse for wear.
Do not try to control the eastern tent caterpillar by torching the nests. Torching with a flaming kerosene-soaked rag tied to the end of a pole is not only dangerous but also causes permanent damage to the tree.
The best method of control is to spray the foliage nearest the web with an organic pesticide such as Thurcide or Dipel. These pesticides contain the BT bacteria that kill the feeding larvae from the inside out. They are approved for use by organic gardeners. To obtain maximum effectiveness, apply in the evening to the foliage in the feeding area. A single application will provide protection for three to four days; it will take a few days before you see evidence of the treatment. The smaller the larvae, the better the control. As the larvae grow larger, they become more difficult to kill with BT.
Use a fresh supply of these organic pesticides, not an unused portion from last year. Once the bottle is open, the effectiveness decreases with time. Unless you are going to be using them to control other pests in your garden, such as cabbage loopers, bagworms or corn-ear worms, purchase the smallest container possible.
In mid to late summer, you’ll see similar webs on a wide variety of woody plants. These are created by the fall webworm. The same treatments can be used to control these pests. In July, you may also see webs on two-needle pines such as Virginia pine and mugo pine. To control the pine sawfly creating them, you’d need the hard pesticide Sevin.

Is My Compost Safe to Use?

Q I shredded some sunflowers in my composter this past fall. I forgot that they are like walnut trees and put out a mild toxin that can negatively affect other plants. Can I use this ­compost? Or should I just throw it out?

–Mike Morgan, Bowie

A The composting process destroys the enzymes that cause the allelopathic effect, so you can use your compost.

Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

The spring of 2016 will be remembered as a short spring and a very short summer followed by a short fall — all within four weeks between March and April. Those 70-degree days in mid March stimulated the vegetative buds in many woody ornamentals to swell, causing the winter bud scales to drop to the ground. This left the buds susceptible to damage by freezing temperatures.
Some Bay Weekly readers have reported buds on their hydrangeas turning brown and drooping, which has never happened before. Others have reported that the new growth on their Euonymus shrubs is turning white and wilting. Others have reported that that frosty nights have caused their American hollies to develop yellow leaves that drop to the ground. They seem to forget that hollies lose their leaves in spring as they start to grow new leaves. The difference is that this year, the transition from old to new is occurring earlier than ­normal.
The peach crop will most likely be sparse this year because most of the trees were in full bloom when the frost hit. Once flower petals begin to unfurl, they lose their cold-hardiness. Late-blooming varieties will produce peaches because their flower buds were still closed at the time of the last frost.
Early asparagus spears wilted to the ground in the section of the garden where I had tilled the soil to control weeds. Where the garden was not freshly tilled and the soil was firm, the early spears were not affected. The difference is due to the heat loss from the soil, which provides frost protection. Where the surface soil was loose, there was not sufficient heat retention to provide frost protection close to the ground. I have seen similar results in gardens where the asparagus beds are mulched. The mulch prevents heat loss from the ground, resulting in the early-rising spears vulnerable to frost.
But plants are survivors. By the first of June, everything will just about look the same, regardless of late-frost damage.

Planting Schedule
If you are anxious to get dirt under your fingernails, this is the time for planting potatoes, onions, cabbage, broccoli, lettuce, cabbage, Chinese cabbage, radishes, kohlrabi, cauliflower, spinach and bak-choi.
Delay planting tomatoes, peppers, melons, squash and cucumbers until the second week in May. If you are using stakes or cages to grow your tomatoes, remember to spray them thoroughly with a 10 percent bleach solution before installing them. There is evidence that spores of blight on last year’s tomato plants can over-winter on the stakes and cages.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

As the trumpets of daffodil petals herald spring, we see clumps growing in roadside banks as well as in gardens. Pretty as they are, the flowers in those large clumps are not as large as those of single plants or smaller clumps. Crowded bulbs are smaller bulbs and thus produce smaller flowers due to a lower reserve of food.
Professional gardeners dig up and thin out clumps of daffodils every five or six years. This practice allows them to not only maintain flower size but to also expand plantings.
If you would like to lift and thin your bulbs, now is the time to take the first step. First, use a large plant label or planting stake with a weatherproof tag to mark the location of each clump to be dug, and identify its flower color. After the foliage dies down to the ground, give the blubs a couple of more weeks to mature. Foliage will die more slowly in clumps growing under partial shade than those growing in full sun.
To minimize damage to the bulbs, use a fork spade for digging and lifting out the bulbs. Start digging at least three or four inches away from the ring of dead foliage. Lift the bulbs and spread them on the ground to dry in the full sun for an hour or so. After the soil on the bulbs has dried, remove it by rubbing gently with your hands. Avoid damaging the tunic, the thin papery covering on the bulbs. Do not attempt to separate the bulbs from each other at this time.
After harvesting, spread the bulbs on a flat surface in a well-ventilated room under cover to finish drying for a few weeks. Then place them in mesh bags or screen storage trays, and store them in a cool, dry place protected from rodents.
In September, plant the bulbs where you want them to bloom next spring.

Is salt damage reversable?

Q Is there any way to compensate for winter salt damage to trees and ­bushes? Also affected is the grass strip ­paralleling the road.

–Farley Peters, Fairhaven

A Most of the damage caused by salt is due to salinity, which kills plant roots. If the sodium level in the soil is equal to or higher than that of potassium, then the damage is more likely related to nutrition. Have the soil tested to see if there is sufficient potassium.

Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

My old friend Bill Burton and I once discussed eating freshly harvested rhubarb as kids during hot summer days in New England, where every home had a rhubarb patch in the backyard. Bill raved about his mother’s rhubarb-custard pie, while I raved about my mother’s strawberry-rhubarb pie. I can still picture myself sitting on the back stairs of our home with a fist full of sugar in my left hand and a freshly harvested stalk of rhubarb in my right. Before each bite, I would dredge the base of the rhubarb stem in the sugar.
Those were the days.
Rhubarb is a vegetable, not a fruit, although we tend to limit its use to making desserts. One of the great features of rhubarb is that it can be blended with other fruit such as strawberries, blueberries, apples, pears and apricots as the rhubarb absorbs the taste of the fruit. In other words, you can make a tasty blueberry pie using only one cup of blueberries and two cups of chopped rhubarb.
Rhubarb grows best in well-drained soil in full sun. It can tolerate partial shade, but it will produce spindly stems. Since you consume only the stem, the fleshier the stem the better. Never eat the leaves because they contain oxalic acid, which will cause swelling of the tongue.
I have seldom seen rhubarb sold in a garden center, though it is commonly listed in seed catalogs. If you order rhubarb for your garden, you will receive in the mail what appears to be a dried-up brown stub. For best results, place it in a cup of water for five days before planting.
There are various clones of rhubarb with stems ranging from green to various shades of green to red and red only. There is even a clone labeled Strawberry-rhubarb. I can assure you that it does not have a strawberry flavor.
Rhubarb likes mildly acid soil with a moderate amount of organic matter. When planting rhubarb, I dig a hole the size of a half-bushel basket and add two to three shovels-full of compost and a handful of agricultural limestone, then mix thoroughly.
Allow the rhubarb to grow without harvesting for at least two years before pulling your first stems. During your first harvest on the third year of growth, remove no more than half of the stems at any one time and allow one month between harvests.
If you see a flower head develop in the center of the clump, remove it with a sharp knife two to three inches from the ground. Allowing the plant to produce seeds during the first three years of growth will weaken the clump.
Never try growing rhubarb in a large container or in a raised bed. The roots are sensitive to high temperatures, which will cause the plant to die in mid-summer as rooting media rises in above-ground containers or beds.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

A successful harvest depends on the right bulbs for our hours of light

Onions are good for your health, and generally they are easy to grow. Let me give you some advice on growing them successfully.
Plant onion sets and you’ll harvest only green onions. Most sets you buy are short-day onions, which produce bulbs only when grown during the winter months with 10 daylight hours or less. Planted in the spring, as daylight hours grow longer, they produce only onion tails, your green onions.
To grow onion bulbs, you must buy either long-day or intermediate, aka day-neutral, onions. They are shipped in bundles of 75 or more seedlings. Unless you are familiar with a particular variety, I suggest planting two or more varieties. Harvesting will be easier if you keep each separate in the garden, as they’ll mature at different times.
Onions perform best in high organic soils with a nearly neutral pH.
The spacing between onion plants is based on the mature bulb size. The most desirable bulb size for kitchen use is one and a half to two and a half inches. For those sizes, use a four-by-four-inch spacing. Bermuda and Walla Walla-size onions need more space; plant them in six-by-six-inch spacing. Those spacings allow room for the bulbs to grow and for you to cultivate between the plants without damaging the bulbs.
Fertilize two to three weeks after planting and monthly thereafter. Don’t let the soil dry out; onions have a very limited root system, and there is a high population of plants in a limited area.
Neck rot of onions can be a serious storage problem. Avoid it by knocking the foliage to the ground just as the bulbs begin to mature in late July and August, depending on the variety. Do so as soon as the color of the foliage begins to fade and the tops of the onion tails start turning brown. I use the back of a garden rake.
Leeks want four-by-four-inch spacing as they do not produce bulbs but do produce thick stems. They have the same growing requirements as onions.
Garlic planted last fall is now in need of fertilizer. Like onions, garlic plants have a limited root system and respond well to fertilizer and water. Remove the flower buds as they begin to form, mid- to late June, depending on variety. If the garlic plants flower and produce seeds, both bulb and cloves will be smaller. For large cloves of elephant garlic, early removal of the flower stem is doubly important.

Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.